1. Field of the Invention
This invention relates to an apparatus for transporting personnel or materials from an elevated location to a lower location.
The development of high rise structures has been accompanied by serious evacuation problems. Tall buildings present serious obstacles to rescue personnel seeking to remove a structure's occupants from upper floors. Rescue ladders seldom reach beyond eight stories so that occupants beyond this level and above the fire line are poorly served by conventional rescue methods.
Alternative methods of rescue such as helicopter evacuation are often impeded by smoke interfering with a pilot's vision or by rooftop structural limitations. Furthermore, the rotor wash of a helicopter can spread or otherwise intensify a fire. Finally, seriously inclement weather or high winds can ground rescue aircraft.
Rappelling techniques, in which personnel are vertically lowered along the outside surface of a building, have been proposed as another rescue alternative for skyscrapers. Examples of such vertical escape techniques can be found in U.S. Pat. Nos. 121,796 and 409,511. These methods, however, are unsuited for use in any situation where flames or any other obstacles obstruct the route of descent. To overcome these deficiencies, various apparatus and techniques have been evolved whereby the line of descent follows a diagonal rather than a vertical slope, carrying persons away from the building rather than along its side. Consequently, persons or objects can be transported out of the danger zone much faster than with vertical rappelling techniques. One such method employs a Tyrolean traverse utilizing a telpher, or guide line, suspended between an elevated embarkation point and a lower receiving point. A load-carrying device is suspended from the guide line and is capable of traversing the length thereof. One such device, described in U.S. Pat. No. 249,847, relates to a fire rescue apparatus based at a lower elevation, comprising a unitary windlass for tightening and loosening two guide lines suspended between the embarkation and receiving points. A carrying means is suspended from each guide line, and an endless traveling line, or lifeline, passes through a pulley secured at the elevated embarkation point. The lifeline is connected to each carrier means and passes around a windlass which imparts an alternate longitudinal movement to each side of the lifeline. This arrangement results in the carrying means suspended from one guide line being lowered while the carrying means suspended from the other guide line is simultaneously raised. This double guide line method is inherently more efficient than a single guide line traverse because it is simultaneously bidirectional, i.e., there is simultaneous upward and downward transport capability. In addition, motive power requirements are reduced because the downward bond load counterbalances the upward bound load and vice versa.
Other transport devices empolying a carrier means suspended from a guide line are disclosed in U.S. Pat. Nos. 38,078; 89,686; 293,177; 293,322; 317,704; 430,225; 734,230; 3,826,335; and 4,056,167.